Abstract

Escherichia coli and Staphylococcus aureus are two food pathogens that cause severe food poisonings. Another problem found on a global level is the continuous increase of antimicrobial resistance in bacteria isolated from food. This study aimed to evaluate the antibacterial activity of Lactobacillus plantarum against pathogenic bacteria including E. coli and S. aureus and to study if L. plantarum with antibacterial activity contained the most plantaricin genes or not. A total of 50 lactic acid bacteria isolates (LAB) were evaluated for antibacterial activity and identified plantaricin genes by polymerase chain reaction (PCR) methods. Seven LAB isolates with antibacterial activity against S. aureus and E. coli were identified as Lactobacillus based on morphological physiological and biochemical properties. Using species-specific PCR and 16S rRNA gene sequencing, B0039 was identified as Lactobacillus paracasei, other isolates were identified as L. plantarum. 3 strains tested positive for all the genes in the plnABCD operon. The plnEFI operon was detected in four strains. Genes encoding for the two-peptide plnJ/K were detected only in 2 strains. Finally, the plnG/V was also found in 3 strains of L. plantarm. The plantarum gene sequences of B0055 were 97 to 100% similarity with the L. plantarum WCFS1. The findings suggest that LAB with bacteriocin genes can be used as an alternative mechanism to control drug resistant foodborne pathogens.

Key worlds: Lactobacillus, antibacterial activity, plantaricin gene, Staphylococcus aureus, Escherichia coli.